Patent Literature 1 describes a layered composite panel construction member having recessed portions in a back surface thereof. The panel construction member is mounted to a ceiling or a wall by engaging mounting metal fittings with the recessed portions, and mounting the panel construction member to the ceiling or the wall by means of the mounting metal fittings.
Patent Literature 2 describes an exterior panel having grooves in a back surface and end faces thereof. The exterior panel is mounted to a frame of a curtain wall unit by engaging mounting metal fittings with the grooves, and mounting the exterior panel to the frame of a curtain wall unit by means of the mounting metal fittings.
Patent Literature 1: Japanese Patent Publication 2007-332539 A
Patent Literature 2: Japanese Utility Model Publication H5-10609 A
In both Patent Literatures 1 and 2, the mounting metal fittings do not contribute to the improvement of flexural strength and flexural rigidity of the panel, and the flexural strength and flexural rigidity of the panel after being mounted are relatively low, since the mounting metal fittings are disposed on the four corners (corner portions) of the panel. When an exterior panel is mounted by the way of Patent Literature 2, an appearance of the exterior panel is unattractive, since the mounting metal fittings are exposed on the end faces of the exterior panel.